All basic research carried out within the Clinical Neurophysiology Program utilizes the same population of patients. The Core exists within a larger Epilepsy Surgery Program which provides state-of-the-art clinical care for this patient population and supports other complementary (largely clinical) research activities. The Core consists of an 8-bed Telemetry Unit which provides cable EEG telemetry with scalp and sphenoidal or intracerebral electrodes and video monitoring; complete surgical facilities for stereotactic placement of depth electrodes, as well as placement of strip or subdural grid electrodes where necessary, and subsequent surgical resection; personnel and equipment for ancillary diagnostic testing, including X-ray computed tomography, magnetic resonance imaging, positron emission tomography, digital subtraction and magnetic resonance angiography, specialized neuropsychological testing, intracarotid amobarbital procedures and quantitative EEG analysis; and support personnel which includes three neurosurgeons, three neurologists with special training in epilepsy and clinical neurophysiology, a psychiatrist, a neuropsychologist, neurology, neurohehavior, and clinical neuropsychology postdoctoral fellows, a clinical nurse specialist and other nurses, telemetry technologists, an electronics technician, an occupational therapist, a social worker, a patient care coordinator, the CNP program coordinator, and an administrator. All patients who are subjects for CNP research projects are treated according to a four-phase clinical protocol: Phase I - presurgical evaluation not requiring intracranial electrodes; Phase II - presurgical evaluation requiring intracranial electrodes; Phase Ill - surgical resection and pathological diagnosis; and Phase IV - postoperative follow-up with respect to epileptic seizures and psychosocial adaptation. Diagnostic and surgical procedures arc standardized for best patient care, which also facilitates the application of clinical data to basic research projects. All activities within the Core that are considered patient care are financially supported by the hospital and third party payers. The specific aims of the Core are: 1) to assure that all patients entered into the CNP protocols receive the best possible clinical care, and that research projects do not create additional risk, discomfort, or financial burden; 2) to ensure that all clinical data necessary for carrying out CNP research projects are made available to CNP investigators; 3) to increase safety and efficacy of presurgical evaluation and surgical treatment based on clinical data, CNP basic research, and advances made elsewhere; and 4) to coordinate other non-CNP research projects which involve CNP patients and may impact on CNP research.